Thermoelectric-based heating and cooling system

ABSTRACT

Disclosed is a heating, ventilation and air conditioning system for a vehicle that operates in a heating mode, a cooling mode or a demisting mode. The system includes a first circuit having first pump for circulating a first medium therein, a second circuit having a second pump for circulating a second medium therein and a thermoelectric module having a first surface in thermal contact with the first medium and a second surface in thermal contact with the second medium.

BACKGROUND

1. Field of the Invention

The present invention generally relates to heating, ventilation and airconditioning (“HVAC”) systems for a vehicle, and more particularly toHVAC systems having thermoelectric modules for providing heating andcooling to a passenger compartment of the vehicle.

2. Description of the Known Technology

In a conventional vehicle, such as an automobile, the heating of thepassenger compartment is accomplished by running engine coolant,typically a mix of water and glycol, through a heat exchanger and thenblowing air through the heat exchanger and into the passengercompartment. The drawback with this is that the heat exchanger will notprovide heat until the engine has caused the coolant to warm up. Incolder climates, the time to warm up the coolant can be lengthy, therebydelaying warming of passengers of the automobile.

Furthermore, newer engines and powertrain arrangements are beingdeveloped where the engine does not produce as much excess heat for thecoolant to absorb. Some examples include direct injection engines andhybrid powertrains. For these types of engines and powertrains, thetemperature of the coolant can take a very long time to rise to a levelthat will allow for adequate heating of the passenger compartment whenusing a conventional heating system.

Therefore, it is desired to provide a HVAC system that provides heat tothe passenger compartment of the vehicle more quickly than aconventional system.

BRIEF SUMMARY

In overcoming the drawbacks and limitations of the known technologies, asystem of heating and cooling the passenger compartment of an automobileis disclosed. The heating and cooling system includes a first circuitand a second circuit. The first circuit includes a first pump forcirculating a first medium therethrough, a first heat exchanger and athird heat exchanger. The second circuit includes a second pump forcirculating a second medium therethrough, a second heat exchanger and afourth heat exchanger. Additionally, the system includes athermoelectric module having a first surface in thermal contact with thefirst heat exchanger and a second surface in thermal contact with thesecond heat exchanger.

The system operates in a heating mode, a cooling mode and a demistingmode. In the heating mode, an electrical current is passed through thethermoelectric module so that the second side of the thermoelectricmodule warms the second medium through the second heat exchanger. Anengine, which is operatively engaged with the first circuit, warms thefirst medium. As the first and second mediums are warmed, the first andsecond pumps circulate the mediums through the third and fourth heatexchangers respectively.

The third and fourth heat exchangers are located near a blower.Generally, the third heat exchanger is located between the blower andthe fourth heat exchanger such that blower will move air through thethird heat exchanger before moving air through the fourth heatexchanger. After the air passes through the third and fourth heatexchangers, the air enters the passenger compartment of the automobile.

In the cooling mode, an electrical current is passed through thethermoelectric module so that the second side of the thermoelectricmodule cools the second medium through the second heat exchanger. Thesecond pump circulates the cooler second medium through the fourth heatexchanger. In this mode, the first medium is directed through the secondbypass line by the second double switching valve. By utilizing thesecond bypass line, the heated first medium is either reduced or notdirected through the third heat exchanger. The air passing through thethird heat exchanger will not be heated or will be heated by a reducedamount, while the air passing through the fourth heat exchanger will becooled.

In the demisting mode, the air provided by the blower is first cooledbefore it is heated and/or passed to the passenger compartment. Byinitially cooling the air, moisture can be removed from the air viacondensation. One way to accomplish this is through the addition ofanother heat exchanger placed between the blower and the third heatexchanger. Through the use of bypass lines and double switching valves,the cooled second medium will be directed to the heat exchanger placedbetween the blower and the third heat exchanger. The air provided by theblower will first be cooled by the heat exchanger placed between theblower and the third heat exchanger before the air is heated by thethird heat exchanger. Alternatively, the third heat exchanger 32 may besplit into multiple portions, such that some portions may heat and otherportions may cool.

Another way of accomplishing demisting is through the addition ofmultiple bypass lines and double switching valves. The bypass lines anddouble switching valves will direct the first medium to the fourth heatexchanger and will direct the second medium to the third heat exchanger.By directing the cooler second medium to the third heat exchanger andthe warmer first medium to the fourth heat exchanger, the air providedby the blower will first be cooled by the third heat exchanger before itis warmed by the fourth heat exchanger. Other alternative fluid pathsand other heat exchanger configurations may also be utilized.

These and other advantages, features and embodiments of the inventionwill become apparent from the drawings, detailed description and claimswhich follow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an HVAC unit embodying the principles ofthe present invention;

FIG. 2 is a block diagram of a second embodiment of an HVAC unitaccording to the principles of the present invention and including asupplemental heating source and cooling source;

FIG. 3 is a block diagram of a third embodiment of an HVAC unit withaccording to the principles of the present invention and including ademisting heat exchanger; and

FIG. 4 is a block diagram of a fourth embodiment of the HVAC unit withbypass lines for transferring first and second mediums between a thirdheat exchanger and a fourth heat exchanger.

DETAILED DESCRIPTION

Referring to FIG. 1, the various components of a HVAC unit 10 are shown.The HVAC unit 10 includes a first circuit 12 having a first pump 14, asecond circuit 16 having a second pump 18, and a thermoelectric module20 having a first surface 22 and a second surface 24 in thermalcommunication with the first and second circuits 12, 16, respectively.The first pump 14 circulates a first medium through the first circuit,and the second pump 18 circulates a second medium through the secondcircuit 16.

In the context of this description, the term “pump” is used in its broadsense of its ordinary and customary meaning and further includes anyconventional pump, J×B (J Cross B) pump, electrostatic pump, centrifugalpump, positive displacement pump, gear pump, peristaltic pump or anyother medium moving device or combination thereof that is known or laterdeveloped.

Generally, the first and second mediums are a liquid having a mix ofwater and glycol. Alternatively, the first and/or second mediums may bea fluid, gas or multipurpose solid-liquid convection medium.

In the context of this description, the term “thermoelectric module” isused in a broad sense of its ordinary and customary meeting, which is(1) conventional thermoelectric modules, such as those produced byMarlow Industries, Inc. of Dallas, Tex., (2) quantum tunnelingconverters, (3) thermionic modules, (4) magneto caloric modules, (5)elements utilizing one, or any bi-combination of, thermoelectric,magneto caloric, quantum tunneling and thermionic effects, (6) acousticheating mechanisms, (7) thermoelectric systems described is U.S. Pat.No. 6,539,725 to Bell, (8) any other sold state heat pumping device (9)any combination, array, assembly and other structure of (1) through (8)above.

In thermal communication with a first heat exchanger 26 is the firstsurface 22 of the thermoelectric module 20. The first heat exchanger 26is in turn in thermal communication with the first medium of the firstcircuit 12. In thermal communication with a second heat exchanger 28 isthe second surface 24 of the thermoelectric module 20. This second heatexchanger 28 is likewise in thermal communication with the second mediumof the second circuit 16.

Preferably, an internal combustion engine 30 is operatively engaged withthe first circuit 12 such that the first medium is circulated by thefirst pump 14 and is used to cool the engine 30. Alternatively, theengine 30 can be any heat generating source that is known or laterdeveloped.

Connected to the first circuit 12 is a third heat exchanger 32 andconnected to the second circuit 16 is a fourth heat exchanger 34, bothof which are used to condition (heat or cool) air to be provided to thepassenger compartment. Accordingly, proximate to the third and fourthheat exchangers 32, 34 is a blower 36. As indicated by the arrow 38, theblower 36 moves air through the third heat exchanger 32 and the fourthheat exchanger 34 before moving the air into the passenger compartmentof an automobile. The blower 36 may be a conventional blower, fan,electrostatic blower, centrifugal blower or any air moving system thatis known or later developed.

Preferably, the first circuit 12 has a fifth heat exchanger 40,generally a radiator, for cooling the first medium within the firstcircuit 12. Alternatively, the fifth heat exchanger 40 may be a heatsink or any device that absorbs or rejects heat including thetraditional radiator, frame or other vehicle parts. A first bypass line42 and a first double switching valve 44 are connected to the firstcircuit 12 such that the first double switching valve 44 can selectivelydirect the first medium through the first bypass line 42 instead of thefifth heat exchanger 40. By circulating the first medium through thefirst bypass line 42 instead of the fifth heat exchanger 40, the firstmedium can be heated more quickly by the engine 30 because the fifthheat exchanger 40 will not have an opportunity to cool the first medium.This is beneficial when the first medium is very cold.

In the context of this description, the term “double switching valve” isused in its broad sense of its ordinary and customary meaning andfurther includes any valve or medium directing device or combinationthereof that is known or later developed.

The first circuit 12 may also have a second bypass line 46 and a seconddouble switching valve 48. The second double switching valve 48 canselectively direct the first medium through the second bypass line 46(during cooling mode operation) instead of through a section of thefirst circuit 12 that includes the third heat exchanger 32. Bycirculating the first medium through the second bypass line 46, thefirst medium will be unable to transfer heat to the third heat exchanger32, and thus air provided by the blower 36 will not be heated by thethird heat exchanger 32. Additionally, the temperature of the firstsurface 22 of the thermoelectric module 20 will not be affected by thefirst medium. This can be advantageous when the HVAC unit 10 is coolingthe passenger compartment of the automobile.

The HVAC unit 10 operates in either a heating mode or a cooling mode. Inthe heating mode, the direction of the current flowing through thethermoelectric module 20 will be such that the first surface 22 coolsand the second surface 24 warms. The second surface 24 will pass theheat through the second heat exchanger 28 and to the second medium. Asthe second medium is passed through the fourth heat exchanger 34, theair provided by the blower 36 is heated thereby. This augments anyheating of the air by the third heat exchanger 32.

As the engine 30 warms up, it heats the first medium that will becirculated through the third heat exchange 32 and the first heatexchanger 26. The heat of the first medium is passed through the firstheat exchanger 26 to first surface 22 of the thermoelectric module 20.By warming the first surface 22 of the thermoelectric module 20, thedifference in temperature between the first surface 22 and the secondsurface 24 will be minimized, allowing the thermoelectric module 20 tooperate more efficiently.

In a cooling mode, the direction of the current flowing through thethermoelectric module 20 will be such that the second surface 24 of thethermoelectric module 20 cools and the first surface 22 of thethermoelectric module 20 warms. The second surface 24 will cool thesecond medium via the second heat exchanger 28 and, as the cooled secondmedium is passed through the fourth heat exchanger 34, the air, providedby the blower 36, is cooled before entering the passenger compartment.

In this mode, the first medium is directed through the second bypassline 46 by the second double switching valve 48. By utilizing the secondbypass line 46, the heated first medium is not directed through thethird heat exchanger 32 and subsequently the first heat exchanger 26 andthe first surface 22 of the thermoelectric module 20. The temperature ofthe first surface 22 of the thermoelectric module 20 therefore notheated, remaining closer in temperature to the second surface 24. Asstated before, by having a low temperature differential between thefirst surface 22 and a second surface 24 of the thermoelectric module20, the thermoelectric module will operate more efficiently.Additionally, because the third heat exchanger 32 will not be heated bythe first medium, air passing through the third heat exchanger 32 willnot be heated.

Generally, the first circuit 12 will have a branch circuit 50 having itsown pump 52, valve 54 and heat exchanger 56. The branch or third circuit50 is used to supplement the cooling of a portion of the first mediumand the first surface 22. For example, when the valve 54 is configuredto allow a portion of the first medium to flow through the branchcircuit 50, the heat exchanger 56 of the branch circuit will aid in thecooling of the first medium. It is noted that during this suchoperation, valve 48 will also be directing a portion of the first mediumacross bypass line 46. When the valve 54 is configured to prevent thefirst medium from circulating through the branch circuit 50, the heatexchanger 56 will not supplement the cooling of the first medium.

Referring now to FIG. 2, another HVAC unit 10′ is shown. This unit 10′is the same as that discussed previously, except, the first circuit 12includes a heat generating system 60 located between the engine 30 andvalve 48 and the third circuit 50 includes a cold generating system 61located between the heat exchanger 56 and the first heat exchanger 26. Abypass line 58 and associated double switching valve 62 are alsoprovided so that the first medium may be bypassed around the heatgenerating system 60, if desired. The heat generating system 60 may beone or more of any system that generates, captures or releases heat,such as a battery, an electronic device, an internal combustion engine,an exhaust of a vehicle, a heat sink, a heat storage system such as aphase change material, a positive temperature coefficient device or anyheat generating system that is known or later developed. The thirddouble switching valve 62 will direct the first medium through eitherthe third bypass line 58 or the heat generating system 60. Bycirculating the first medium through the heat generating system 60, thefirst medium can be heated more quickly than by the engine 30 alone.

A bypass line 59 and associated double switching valve 63 are alsoprovided so that the first medium may be bypassed around the coldgenerating system 61, if desired. The cold generating system 61 may beone or more of any system that generates, captures or releases cold,such as a thermoelectric module, a heat sink, a cold storage system suchas a phase change material or any cold generating system that is laterdeveloped. The double switching valve 63 will direct the first mediumthrough either the bypass line 59 or the cold generating system 61. Bycirculating the first medium through the cold generating system 61, thefirst medium can be cooled more quickly than by the heat exchanger 56alone.

Referring now to FIG. 3, another embodiment of a HVAC unit 10″ is shown.This unit 10″ is substantially the same as that discussed above andshown in FIG. 1. However, a demisting heat exchanger 64 is provided inthe second circuit 16 as a bypass, via double switching valve 66, aroundthe fourth heat exchanger. Thus, the demisting double switching valve 66will selectively direct the second medium through the demisting heatexchanger 64 instead of the fourth heat exchanger 34. As indicated bythe arrow 38, the blower 36 will blow air first through the demistingheat exchanger 64. This initial cooling of the air removes moisture fromthe air via condensation.

After the air is initially cooled, the air may be cooled or heated bythe third heat exchanger 32. The valves 67, 69 and 71 will direct thefirst medium through either first circuit 12, where it is warmed by theengine 30, or through the third circuit 50, where it is cooled by theheat exchanger 56, and then through the third heat exchanger 32.Alternatively, the double switching valve 48 may prevent the firstmedium from traveling through the third heat exchanger 32, therebypreventing any heating or cooling the air by the third heat exchanger32.

Referring now to FIG. 4, another embodiment of the HVAC unit 10′″ isshown. The HVAC unit 10′″ is substantially the same as the discussedabove and shown in FIG. 1. However, a fourth bypass line 68 and a fifthbypass line 70 circulate the second medium to the third heat exchanger32 and a sixth bypass line 76 and a seventh bypass line 78 circulate thefirst medium to the fourth heat exchanger 34.

A fourth double switching valve 72 will direct the second medium fromthe second circuit 16, through the fourth bypass line 68, and to thethird heat exchanger 32. A fifth double switching valve 74 will directthe second medium from the third heat exchanger 32, through the fifthbypass line 70, and to the second circuit 16.

A sixth double switching valve 80 will direct the first medium from thefirst circuit 12, through the sixth bypass line 76, and to the fourthheat exchanger 34. A seventh double switching valve 82 will direct thefirst medium from the fourth heat exchanger 34, through the seventhbypass line 78, and to the first circuit 12.

By directing the cooler second medium and warmer first medium throughthe third heat exchanger 32 and the fourth heat exchanger 34respectively, the third heat exchanger 32 will cool air blown by theblower 36 before the air is heated by the fourth heat exchanger 34. Theinitial cooling of the air removes moisture from the air viacondensation.

Additionally, an eighth double switching valve 84 may be connected tothe second bypass line 46 and the first circuit 12. The eighth doubleswitching valve 84 will direct the first medium through either thesecond bypass line 46 or the first heat exchanger 26. By circulating thefirst medium through the second bypass line 46, the first heat exchanger26 will not be in thermal communication with the warmer first medium.This can be advantageous when the HVAC unit 10 is in the cooling mode.The heat contained within the first medium will be unable to transferheat to the first surface 22 of the thermoelectric module 20. Byminimizing the temperature differential between the first surface 22 andthe second surface 24 of the thermoelectric module 20, thethermoelectric module 20 will operate more efficiently.

As a person skilled in the art will readily appreciate, the abovedescription is meant as an illustration of implementation of theprinciples of this invention. This description is not intended to limitthe scope or application of this invention in that the invention issusceptible to modification, variation and change, without departingfrom spirit of this invention, as defined in the following claims.

1. A heating and cooling system for a vehicle, the heating and coolingsystem comprising: a first circuit having a first pump for circulating afirst medium therethrough; a second circuit having a second pump forcirculating a second medium therethrough; a first heat exchanger inthermal communication with the first medium; a second heat exchanger inthermal communication with the second medium; and a thermoelectricmodule having a first surface in thermal communication with the firstheat exchanger and a second surface in thermal communication with thesecond heat exchanger, whereby the second surface is performing one ofheating and cooling the second medium; wherein the system is configuredto heat a passenger compartment of the vehicle when a heating mode isselected; wherein current flows in a first direction through thethermoelectric module such that the first surface cools the first heatexchanger and the second surface heats the second heat exchanger whenthe heating mode is selected; wherein the system is further configuredto cool the passenger compartment of the vehicle when a cooling mode isselected; and wherein current flows in a second direction through thethermoelectric module such that the first surface warms the first heatexchanger and the second surface cools the second heat exchanger whenthe cooling mode is selected.
 2. A heating and cooling system for avehicle, the heating and cooling system comprising: a first circuithaving a first pump for circulating a first medium therethrough; asecond circuit having a second pump for circulating a second mediumtherethrough; a first heat exchanger in thermal communication with thefirst medium; a second heat exchanger in thermal communication with thesecond medium; a thermoelectric module having a first surface in thermalcommunication with the first heat exchanger and a second surface inthermal communication with the second heat exchanger, whereby the secondsurface is performing one of heating and cooling the second medium; andan engine being operatively engaged with the first circuit.
 3. Thesystem of claim 2, further comprising a third heat exchanger in thermalcommunication with the first medium.
 4. The system of claim 3, furthercomprising a blower configured to move air through the third heatexchanger.
 5. The system of claim 2, further comprising a third heatexchanger in thermal communication with the second medium.
 6. The systemof claim 5, further comprising a blower configured to move air throughthe third heat exchanger.
 7. The system of claim 2, further comprising athird heat exchanger being operatively engaged with the first circuit.8. The system of claim 7, wherein the third heat exchanger is aradiator.
 9. The system of claim 7, wherein the first circuit furthercomprises an at least one bypass line and an at least one valveconfigured to direct the first medium through one of the at least onebypass line and the first heat exchanger.
 10. The system of claim 2,wherein the first circuit further comprises an at least one bypass line,wherein the first medium is circulated through the at least one bypassline, thereby preventing the first medium from being in thermalcommunication with the first heat exchanger.
 11. The system of claim 10,further comprising an at least one double switching valve configured todirect the first medium through one of the at least one bypass line andthe first circuit in thermal communication with the first heatexchanger.
 12. A heating and cooling system for a vehicle, the heatingand cooling system comprising: a first circuit having a first pump forcirculating a first medium therethrough; a second circuit having asecond pump for circulating a second medium therethrough; a first heatexchanger in thermal communication with the first medium; a second heatexchanger in thermal communication with the second medium; athermoelectric module having a first surface in thermal communicationwith the first heat exchanger and a second surface in thermalcommunication with the second heat exchanger, whereby the second surfaceis performing one of heating and cooling the second medium; and a thirdcircuit having a third pump, a valve and a sixth heat exchanger, thethird circuit being connected to the first circuit.
 13. The system ofclaim 12, further comprising a cold generating system being operativelyengaged with the third circuit.
 14. The system of claim 13, wherein thethird circuit further comprises an at least one bypass line and an atleast one valve configured to direct the first medium through one of theat least one bypass line and the cold generating system.
 15. The systemof claim 13, wherein the cold generating system is a thermoelectricdevice.
 16. The system of claim 13, wherein the cold generating systemis a cold storage system.
 17. The system of claim 16, wherein the coldstorage system is a phase change material.
 18. The system of claim 5,wherein the second circuit further comprises a demisting heat exchangerand an at least one valve, whereby the at one least valve directs thesecond medium through at least one of the third heat exchanger and thedemisting heat exchanger.
 19. A heating and cooling system for avehicle, the heating and cooling system comprising: a first circuithaving a first pump configured to circulate a first medium therethrough;a second circuit having a second pump configured to circulate a secondmedium therethrough; a first heat exchanger in thermal communicationwith the first medium; a second heat exchanger in thermal communicationwith the second medium; a thermoelectric module having a first surfacein thermal communication with the first heat exchanger and a secondsurface in thermal communication with the second heat exchanger, wherebythe second surface is configured to perform one of heating and coolingthe second medium; and a heat generating system being operativelyengaged with the first circuit wherein the first circuit furthercomprises at least one bypass line and at least one valve configured todirect the first medium through one of the at least one bypass line andthe heat generating system.
 20. The system of claim 19, wherein the heatgenerating system is a battery.
 21. The system of claim 19, wherein theheat generating system is an electronic device.
 22. The system of claim19, wherein the heat generating system is an internal combustion engine.23. The system of claim 19, wherein the heat generating system ispositive temperature coefficient device.
 24. The system of claim 19,wherein the heat generating system is an exhaust of the vehicle.
 25. Thesystem of claim 19, wherein the heat generating system is a fuel cell.26. The system of claim 19, wherein the heat generating system is athermoelectric device.
 27. The system of claim 19, wherein the heatgenerating system is a heat storage system.
 28. The system of claim 27,wherein the heat storage system is a phase change material.
 29. Thesystem of claim 1, wherein the thermoelectric module transfers thermalenergy from the first heat exchanger to the second heat exchanger in theheating mode, and wherein the thermoelectric module transfers thermalenergy from the second heat exchanger to the first heat exchanger in thecooling mode.
 30. The system of claim 1, further comprising a third heatexchanger operatively engaged with the second circuit and configured tobe in thermal communication with an airflow.